title: Identification of human immunodeficiency virus type 1 (HIV-1) gp120-binding sites on scavenger receptor cysteine rich 1 (SRCR1) domain of gp340.
abstract: BACKGROUND
  gp340, a member of scavenger receptor cysteine rich family encoded by Deleted in Malignant Brain Tumors 1 (DMBT1), is an important component in innate immune defense. The first scavenger receptor cysteine rich domain (SRCR1) of gp340 has been shown to inhibit HIV-1 infection through binding to the N-terminal flank of the V3 loop of HIV-1 gp120.
  
  
  RESULTS
  Through homology modeling and docking analysis of SRCR1 to a gp120-CD4-X5 antibody complex, we identified three loop regions containing polar or acidic residues that directly interacted with gp120. To confirm the docking prediction, a series of over-lapping peptides covering the SRCR1 sequence were synthesized and analyzed by gp120-peptide binding assay. Five peptides coincide with three loop regions showed the relative high binding index. An alanine substitution scan revealed that Asp34, Asp35, Asn96 and Glu101 in two peptides with the highest binding index are the critical residues in SRCR1 interaction with gp120.
  
  
  CONCLUSIONS
  We pinpointed the vital gp120-binding regions in SRCR1 and narrowed down the amino acids which play critical roles in contacting with gp120.
authors.affiliation: The Center for Public Health Research, School of Medicine, Nanjing University, Nanjing 210093, Jiangsu Province, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Chu
authors.forename: Jiahuang
authors.initials: J
authors.lastname: Li
authors.forename: Xilin
authors.initials: X
authors.lastname: Wu
authors.forename: Zichun
authors.initials: Z
authors.lastname: Hua
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Wu
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D015699:HIV Envelope Protein gp120 / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D062105:Molecular Docking Simulation; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000378:metabolism; D025521:Tumor Suppressor Proteins
chemical_list: D002135:Calcium-Binding Proteins; C108174:DMBT1 protein, human; D004268:DNA-Binding Proteins; D015699:HIV Envelope Protein gp120; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; D025521:Tumor Suppressor Proteins